Please use PhysX 3 :)

[Tgirgis]

@Sabino98;220829

Please, Epic developers, let me know if you are going to improve PhysX performance.
PS. If I bought UE4 and had access to the source code, would I be able to create my own threads or implement Bullet/ODE? Thank you

You can, but not easily. There was some discussion about it on this thread -

How much work is it to replace the physics engine?